Computer users continue to demand increased performance from the computer systems available in the marketplace. Of particular interest have been computer systems with improved display subsystems which provide, among other things, color images, improved image definition, and windowing. Such improvements in display technology not only made the display screens more aesthetically pleasing to the user but also generally make the system easier to use, both important considerations when analyzing marketability.
Recent improvements in display technology have been directed at allowing display systems to manage and mix both graphics data and video data in a windowing environment. In addition to controlling the content of various sections (windows) of the display screen, these display systems must also establish compatibility between the display device (e.g., a raster scan display) and the graphics and video data sources. In the case of graphics data, the display control circuitry must be capable of driving a given display from data received from various sources (for example, VGA, CGA, VRAM) as well as in varying formats (for example, varying numbers of bits per pixel and/or varying numbers of bits per each color in a pixel). Similarly, in the case of video data, the display control circuitry must be capable of handling input data in varying formats, such as RGB and YUV, and of varying numbers of bits per pixel and/or bits per color. All these considerations must be made in view of the ever increasing data transfer speeds.
Many computer users, especially in a windowing environment, employ an on-screen cursor, typically controlled by a mouse, for information input and control. As a result, display system designers must further concern themselves with the generation of the cursor on the display. Some of the factors which must be considered are the user's desired positioning of the cursor on the screen, the overlay of the cursor above the incoming graphics and/or video data, and the relationship of the cursor to any bordering which may be desired around the periphery of the screen.
Thus, the need has arisen for improved apparatus, systems and methods for generating a cursor on a display screen. Such a cursor should be operable in multiple source and windowing environments operating at high speed. Further, the cursor should be operable when the display environment includes such characteristics as bordering and the like.